Ignition Switch: Description and Operation

ACCESSORY OR RUN POSITION

When the ignition switch is in either the ACCESSORY or RUN positions, it connects circuit A1 to circuit A31. Circuit A1 is protected by a 40 amp fuse located in cavity 12 of the Power Distribution Center (PDC), and is HOT at all times.

Circuit A31 connects to the fuse block and feeds the circuits connected to fuses 9, 10, and 11.

RUN POSITION

In the RUN position, the ignition switch connects circuit A2 from 60 amp fuse 13 in the PDC to circuit A22. Circuit A22 connects to the fuse block and feeds the circuits protected by fuses, 17, 18, 19 and 20. Circuit V34 from fuse 20 in the fuse block supplies battery voltage to the vehicle speed control system.

START OR RUN POSITION

When the ignition switch is in either the START or RUN positions, it connects circuit A1 to circuit A21. Circuit A1 is protected by a 40 amp fuse located in cavity 12 of the Power Distribution Center (PDC), and is HOT at all times.

Circuit A21 connects between the ignition switch and the 15 amp fuse located in cavity 6 of the PDC. From the fuse in cavity 6, circuit F86 supplies power to the coil side of the fuel pump relay. At the fuel pump relay, circuit F86 is double pinned and supplies power to the coil side of the Automatic Shut Down (ASD) relay. Circuit F86 also connects to cavity 9 of the Powertrain Control Module (PCM).

Circuit A21 also connects to a bus bar in the fuse block that feeds fuses 21 and 22.

START POSITION

In the START position, the ignition switch connects circuit Al from the 40 amp fuse in cavity 12 of the Power Distribution Center (PDC) to circuit A41. Circuit A41 connects to the contact side of the engine starter motor relay

Also in the START position, the ignition switch connects circuit G9 to ground. Circuit G9 connects to the instrument cluster and park brake switch.